One flag gives your AI agent live control of your Flutter app

You paste code into Copilot, it writes a fix, you copy it back, run it, hit an error, paste that in — the loop is familiar. With Flutter development this gets worse: the agent has no idea whether your emulator is even running, let alone what the widget tree looks like or whether dart analyze is happy.

Flutter 3.44 (released at Google I/O 2026, May 20) shipped an official Dart & Flutter MCP Server that changes this. Enable it with one line in VS Code settings, and GitHub Copilot, Cursor, Claude Code, or Codex CLI gains direct access to 15+ live development tools: hot reload, widget inspector, runtime error analysis, pub.dev search, and more. 1

Extension: Dart-Code.flutter (v3.137.20260601) · 13.97M installs · Free · VS Code Marketplace

The problem: agents operate blind

A typical AI-assisted Flutter session before Flutter 3.44 looked like this:

Ask the agent to add a feature
Agent writes code — and stops there
You run flutter run, watch the emulator
A runtime error surfaces — you copy it, paste it back to the chat
Agent suggests a fix; you apply it, hot-reload manually
Agent has no idea whether the reload worked

Every handoff between the chat panel and the terminal or emulator is a context switch you do by hand. The agent modifies files but never sees the consequences.

The fix: one settings flag

Open VS Code settings (Cmd+, / Ctrl+,), search for dart.mcpServer, and enable it — or add this line to your settings.json:

{
  "dart.mcpServer": true
}

That's all. The Dart extension (v3.114+, bundled with any current Flutter extension install) auto-registers the MCP server using VS Code's native MCP API. 1 No separate install, no mcp.json to write for GitHub Copilot in VS Code.

For Cursor, add an entry to .cursor/mcp.json in your project root:

{
  "mcpServers": {
    "dart": {
      "command": "dart",
      "args": ["mcp-server"]
    }
  }
}

Claude Code and Codex CLI pick up the same JSON format in their respective config files.

What the agent can actually do now

Once connected, the agent gets a set of tools it can call autonomously — no clipboard required. 2

Tool	What it does
`hot_reload`	Triggers hot reload on the running app
`hot_restart`	Full restart — clears state
`get_runtime_errors`	Fetches live exceptions from the running app
`widget_inspector`	Reads the current widget tree
`analyze_files`	Runs `dart analyze` and returns diagnostics
`pub_dev_search`	Searches pub.dev for packages
`run_tests`	Runs the test suite
`lsp`	Hover docs, signature help, symbol resolution
`read_package_uris`	Resolves package URIs safely

The bridge is the Dart Tooling Daemon (DTD) — a long-running process the Dart extension starts alongside your app. The MCP server discovers running apps through DTD and connects automatically. Khanh Nguyen (Flutter team) describes it as: 3

"In a big leap forward for AI-assisted development, we are launching Agentic Hot Reload: The MCP server and your favorite coding agent will now automatically find and connect to running Dart and Flutter applications."

The result: the agent modifies a file, calls hot_reload, the app updates, and the agent calls get_runtime_errors to see whether anything broke — all without you touching the keyboard.

Gemini Code Assist showing the list of available Dart MCP server tools in the VS Code chat panel — Gemini Code Assist's `/mcp` command confirming the Dart MCP server is connected with tools including `hot_reload`, `widget_inspector`, and `get_runtime_errors`. 2

See it in action: Agentic Hot Reload demo

The official demo shows Gemini CLI modifying a Flutter star counter app — changing theme colors and animation behavior — while the Android emulator hot-reloads on every iteration. The agent never leaves the terminal.

Agentic Hot Reload: macOS terminal running Gemini CLI on the left, Android emulator updating a Flutter star counter app on the right — Agentic Hot Reload in action — the agent makes code changes and calls `hot_reload` directly; the emulator reflects each update without manual intervention. 4

Connie Ooi (Dart team) summarizes the before/after: 4

"Your coding agent can now automatically hot reload, eliminating the friction of having to manually find and copy Dart Tooling Daemon (DTD) connection URIs."

blog.flutter.devhttps://blog.flutter.dev/whats-new-in-flutter-3-44-b0cc1ad3c527외부 링크

콘텐츠 카드를 불러오는 중…

Dart 3.12 bonus: private named parameters

While you're on Flutter 3.44 / Dart 3.12, the IDE quietly gained support for a quality-of-life language fix that eliminates a specific boilerplate pattern.

Before Dart 3.12, you couldn't use this._field as a named initializing formal parameter. The workaround meant duplicating field names in the constructor signature:

// Before Dart 3.12 — verbose workaround
class Hummingbird {
  final String _petName;
  final int _wingbeatsPerSecond;

Hummingbird({required String petName, required int wingbeatsPerSecond})
      : _petName = petName, _wingbeatsPerSecond = wingbeatsPerSecond;
}

Dart 3.12 allows this._fieldName directly. The compiler strips the leading underscore to derive the public parameter name: 4

// Dart 3.12 — one constructor line
class Hummingbird {
  final String _petName;
  final int _wingbeatsPerSecond;

// ✅ IDE shows named params as: petName, wingbeatsPerSecond
  Hummingbird({required this._petName, required this._wingbeatsPerSecond});
}

// Call site unchanged:
Hummingbird(petName: 'Dash', wingbeatsPerSecond: 75)

The Dart Analysis Server handles this natively — hover, completion, and signature help all surface the public names (petName, wingbeatsPerSecond) while the backing fields stay private. No extension update required beyond having Dart 3.12.

Gotcha: KGP warning on Android builds

If you're upgrading an existing project to Flutter 3.44, Android builds may show a warning about the Kotlin Gradle Plugin (KGP). Android Gradle Plugin (AGP) 9 now treats Kotlin as a built-in feature, but many existing plugins still apply KGP themselves, causing the conflict. 5

The official temporary workaround is to add two lines to android/gradle.properties: 6

android.builtInKotlin=false
android.newDsl=false

Flutter will add these automatically on the next build for most project types. Projects using add-to-app need to add them manually. These flags are temporary — the Flutter team plans to remove them in a future release once the ecosystem has migrated. 6

Known affected plugins include firebase_remote_config, device_info_plus, sentry_flutter, audioplayers, and flutter_reactive_ble. 5 If your build fails on a specific plugin, file an issue with that plugin's maintainer.

Quick reference

Extension ID	`Dart-Code.flutter`
Current version	3.137.20260601
Dart extension	`Dart-Code.dart-code` (auto-installed)
Installs	13.97M
Rating	4.86 / 5 (98 reviews)
Minimum VS Code	1.75.0 (Flutter ext); 1.101.0 (Dart ext)
Minimum SDK	Dart 3.2 / Flutter 3.16
MCP server requires	Dart-Code extension v3.114+
License	MIT
Publisher	Dart Code (Google, verified)

Install on VS Code Marketplace · MCP server docs · dart-lang/ai on GitHub

Cover image: AI-generated illustration.